Photo Gallery The Great Arctic Meltdown
The left-hand image depicts the pattern seen in winters from 1986 to 1991: The Arctic climate was determined by a "tripolar" pattern dependent on the Icelandic Low, the Azores High and a subtropical high in the Pacific. The right-hand image shows the latest development. The pattern is now "dipolar" with cool air being shoved aside as the Icelandic Low and Azores high move in a north-easterly direction. The result is masses of warm air moving into the Arctic region.
The Arctic icecap has been shrinking quickly and temperatures in the region are climbing twice as fast as the global average. Particularly worrisome is the extent to which older, thicker layers of ice have begun to melt.
Throughout this decade, the extent of ice in the Arctic has receded. This image shows the maximum ice cap from 2003.
By 2005, the maximum extent of the ice was smaller.
In 2007, the shrinkage continued.
These two images show areas covered by ice in September 1979 (above) and in September 2005.
This map shows the average maximum extent of Arctic ice in the last 28 years, marked by the yellow line. The red line indicates the maximum reached in 2006 -- at the time, the least amount of ice ever measured.
The year 2007 saw another alarming milestone: For the first time, the Northwest Passage, marked by the yellow line, was completely ice free. The Northeast Passage along the Siberian coast was mostly ice free.
